1. Field of the Invention
The present invention relates to a method of antibiotic susceptibility testing and for determining a minimum inhibitory concentration of the antibiotic and, more particularly, to a method of antibiotic susceptibility testing and for determining a minimum inhibitory concentration of the antibiotic, which both employ dielectrophoresis and the antibiotic inhibiting cell wall synthesis to detect rod-shaped microbes.
2. Description of Related Art
Currently, clinically assessing effects of an antibiotic on pathogenic bacteria is generally achieved by an in vitro test which determines antibiotic susceptibility of the bacteria. There are many such in vitro tests, for example, a minimum inhibitory concentration (MIC) test, a disk-diffusion test, a checkerboard test, a minimum bactericidal concentration (MBC), a time-kill curves test, and so on. These tests can be used according to requirements such as timeliness and accuracy.
Among the tests listed above, the disk-diffusion test is a method that is most common and rapid because this method is simple and economical. However, after the method is executed, only qualitative information can be obtained, and thus this cannot serve as a basis for the regulation of antibiotic doses. Accordingly, if the regulation of antibiotic doses is required, an MIC test can be performed to afford quantitative information which is the basis for the use of antibiotics.
In the traditional MIC test, optical measurement is a common means. When microbes are treated with an antibiotic for 18-24 hours, optical density of the culture medium is measured by a spectrometer so as to determine whether microbial growth is inhibited or not. Accordingly, conventional optical measurement requires at least 18-24 hours for microbial growth. If a microbe grows very slowly, culturing the microbe needs even more time. Therefore, if timeliness is required, for example, diagnosing acute microbial infections such as bacteremia and meningitis, conventional optical measurement is often too slow to resolve critical situations. Hence, meeting clinical emergencies is difficult via conventional optical measurements.
Since conventional methods generally consume several days and are unable to provide timely final results, there is an urgent need to develop a technique for rapidly determining antibiotic susceptibility and a MIC of the antibiotic. The technique of the present invention is able to check whether microbes have antibiotic resistance within 1-2 hours and to afford an antibiotic MIC so as to meet clinical requirements and benefit the public.